Needled non-woven fabrics and method of making the same



3,366,529 NEEDLED' NONWOVEN FABRICS AND METHOD OF MAKING THE SAME A. R.OLSON Jan. 30, 1968 Original Filed Dec. 2, 1964 United States Patent3,366,529 NEEDLED NON-WOVEN FABRICS AND METHOD OF MAKING THE SAME ArthurR. Olson, Walpole, Mass., assignor to The Kendall Company, Boston,Mass., a corporation of Massachusetts Continuation of application Ser.No. 415,338, Dec. 2, 1964. This application Feb. 21, 1967, Ser. No.617,719 13 Claims. (Cl. 161-67) ABSTRACT OF THE DISCLOSURE A porous anddelamination-resistant needled non-woven fabric of one layer oftextile-length, unspun and unwoven fibers having fibrous bundlesdisposed in a direction normal to the fabric and one layer of aretractable, polymeric, thermoplastic film material. The film is in theform of a unified, porous, reticulate network of interconnected,irregular filaments composed solely of the film substance. Some of thefibrous bundles extend through the film network and are bonded to it bythe film substance. A substrate layer of fabric or foam may be addedwith the film network between it and the fiber layer.

These fabrics are produced by assembling a fleece of textile-lengthfibers arrayed in a plane, disposing the fleece on a continuous film ofthermoplastic polymeric material retractable relatively to the fleeceand needling the fibers of the fleece through its other side. Thisproduces a multiplicity of openings through the film and groups some ofthe fibers into fibrous bundles directed through the film openings, in adirection normal to the main plane of the film, and into any substratelayer. The assembly is then heated to retract the film while restrainingit by the multiplicity of fibrous bundles through it to convert the filminto the unified, porous, reticulate network of interconnected irregularfilaments composed solely of film substance, to provide at least 50%open area and with the thickness of the filaments at least 5 times thethickness of the original film.

This application is a continuation of my copending application Ser. No.415,338, filed Dec. 2, 1964, now abandoned.

This invention relates to needle-punched nonwoven fabrics, and moreparticularly to fabrics of this type which are internally reinforced byan open, porous reticulate network of thermoplastic material serving tobond the structure into a coherent, abrasion-resistant fabric.

In distinction to so-called bonded nonwoven fabrics, made by saturatingan unspun and unwoven fibrous fleece with an aqueous polymeri binder,nonwoven fabrics made by a needle-loom process depend for theirintegrity on a mechanically-induced reorientation and interlocking ofsome of the fibers in a fleece. Needled nonwoven fabrics, therefore, donot suffer from the stifiening effect and the matting-down of fiberscustomarily associated with wet bonding. They have a soft hand anddrape, easy conformability and a degree of elongation, high loft, lowdensity, and high insulating value, properties which render themuniquely useful in applications, such as garment linings, to whichbonded nonwoven fabrics are not so Well suited.

The mechanical interlocking of fibers in a needled nonwoven fabric,however, is not as strong a bond as is developed in bonded nonwovenfabrics. Therefore, for uses where tensile strength and abrasionresistance are requisites, as in an exposed liner for boots, shoes, orother apparel, needled nonwoven fabrics are frequently reinforced with alayer of fabric, polymeric foam, film, or combinations of suchmaterials, as described for instance in US. Patent 3,059,312, toJamieson. Combinathe film and any substrate layer on' tions of needledfibrous webs with layers of other material are referred to as needledlaminates in this application.

Even in the case of such laminates, however, tensile strength and, moreparticularly, surface durability and abrasion resistance, leave much tobe desired. Some of the fibers are deflected by the needling operationfrom their normal orientation in the plane of the fabric so that theyare aggregated into fibrous bundles extending down through the fibrouslayer and through any reinforcing substrate which may be present. Thebonds thus formed, however, are still mechanical in nature and aretransient, in the sense that fibrous bundles are wedged into a substratewhich yields slightly as it receives the thrust of the fiber-ladenneedle, and then recovers upon withdrawal of the needle to clasp thefibrous bundle with a firmness which varies with the elastic nature ofthe particular substrate employed. Surface friction or abrasive actionon the face of such needled products, such as results from body actionagainst such a surface, gradually decreases the degree of interlockingof the fibers with each other and with the substrate if present, so thatthe fibers pluck out and are shed from the nonwoven fabric surface.

Therefore it has been proposed to increase the internal integrity ofsuch needled nonwoven fabrics or needled laminates by saturating with abinder. This, however, frequently alters the nature of the product sothat the desirable loft and softness are lost, particularly in view ofthe concentration of binding agent which occurs on the surfaces due tohinder migration during drying. Methods have also been advanced for theuse of coagulants or gelling agents, to minimize binder migration. Sofar as I am aware, however, no methods previously proposed havesucceeded in producing a needled nonwoven fabric or laminate which issoft, lofty, porous, and conformable, and which has a high degree ofinternal integrity enhancing the tensile strength and resistance tofiber shedding, while still preserving the desirable fleece-like freefibrous character of the surface. It is with improvements in the art ofbonding together the fibers which make up needled nonwoven products thatthe present invention is concerned.

I have found that if a fibrous fleece or batt is needled through a filmcomposed of thermoplastic and heatretractable polymeric material, andthe assembly is then subjected to a temperature above the softeningpoint of the film but below the point at which the film becomescompletely fluid, as set forth below, the film is transformed from alightly-apertured but generally impervious layer to a very open andporous reticulate network of fused polymeric material which bonds theinternal fibrous layer of the fabric into a coherent, abrasion-resistantfabric of high tensile strength. At the same time, the film substance ismaintained as a discrete and self-sustaining network: it is not diffusedthroughout the fleece, and in cases where the film has been needled toone surface of a fibrous fleece, that surface is heat-sealing due to thelocalized concentration of thermoplastic substance.

In Canadian Patent 680,521, to Whytlaw, a process is described in whicha fibrous fleece is needle-punched into a thermoplastic mm, and theassembly is subsequently heated to within the softening range of thefilm, to cause the film to bond to the fibrous bundles around theperipheries of the apertures in the film through which the fibrousbundles have been thrust. It is emphasized in said patent, however, thatthe film is of a continuous and unbroken nature between the fibrousbundles, so that if both the film and the fibers have low moistureabsorption, the fabric is said to possess moisture barriercharacteristics; if the fibers are absorbent, the film base is said toserve as a moisture barrier and the punched fibers transmit air but notmoisture. It is preferred by Whytlaw that the heating processbeaccompanied by pressure, so that the fibers are embraced by thesoftened film substance and the fibers and film form an integralstructure. It is also known, according to British Patent 967,159, toheat such a combination of a thermoplastic film, with a fibrous fleeceneedled therethrough, until the film has become completely fluid. Thishas the effect, however, of causing the film to permeate the fleece, andas set forth in said patent, the film character is lost. The diffusionof the film substance throughout the fleece causes a stiffening orbonding action to affect substantially all of the fibers, with theaccompanying decrease in loft, softness, and drape.

Aswill be set forth more fully below, the present invention contemplatesheating the film-fiber assembly not just to the softening range, butabove the softening point of the film while below the point of completefluidity, with the unexpected formation of a unique network of fusedpolymeric material of very high porosity and no moisturebarrierproperties.

This invention will be more clearly understood with reference to theaccompanying drawings, in which:

FIGURE '1 is a magnified cross-sectional view of a fibrous fleeceneedled to a base film of thermoplastic and heat-retractable material.

FIGURE 2 is a magnified cross-sectional view of a fibrous fleece needledthrough a thermoplastic and heatretractable film and also through anunderlying fabric substrate.

FIGURE 3 is a representation, magnified 4 times, of approximately onesquare inch of film through which a fibrous fleece has been needled, andfrom which the fibrous material has been dissolved out prior toheattrcatment. FIGURE 3 is not idealized, but is a tracing of an actualphotograph of a film so treated.

FIGURE 4, also a tracing of an actual photograph, is a representation,magnified 4 times, of a piece of the reticulate thermoplastic networkinto which the film of FIGURE 3 is transformed by heating the compositefilmfiber assembly above the softening point of the film substance,followed by dissolving out all the fibers.

Referring to FIGURE 1, a fleece or batt of textilelength fibers isshownas having been needle-punched through an underlying film ofthermoplastic and heatretractable material 12, so that some of thefibers are gathered into the form of fibrous bundles 14 which 'arechoice of fleece-forming device used will depend onv whether it isdesired to have the fibers predominantly parallelized in the machinedirection, as from a card, or isotropically arrayed as from an air-laymachine.

FIGURE 2 is similar to FIGURE 1, except that the fibrous bundles 14 passthrough an additional substrate in the form of a fabric composed of warpyarns 18 and filling yarns 20.

As film base, any polymeric material in film form may be employed,provided that it is thermoplastic and heatretractable: that is, in thesoftening process, the film tends to shrink and retract. Certainfilm-forming polymeric materials are naturally heat-retractable due totheir chemical nature, while other films are retractable due to theirhaving been unilaterally or biaxially oriented during their manufacture.Suitable films are those prepared from plasticized cellulose esters suchas plasticized cellulose acetate, films prepared from vinyl polymerssuch as polyvinyl chloride, polyvinylidene chloride, copolymers of vinylchloride and vinyl acetate, and polyolefine films such lating value maybe realized through the use of foamed polymeric material such aspolyurethane foam, or both foam and fabric may be used. Novelty is notclaimed for any particular pre-assemblage of textile fibers with areinforcing substrate or substrates, but resides in the uniquely porousconfiguration of the thermoplastic and heat-retractable film afterprocessing, together with its bonded union to the fibrous fleece andsubstrate, if the latter is used.

The above-described fibrous fieece is superimposed upon thethermoplastic film plus any additional substrates desired, and theassembly is then needle-punched, preferably in a continuous operation,by passing it through a needle loom. Such devices are well-known in theart and are not shown. The result of such an operation is to thrustfibrous bundles down through apertures formed in the film, so that thelower face of the assembly is studded with fibrous bundles protrudingfrom said face. The tracing of FIGURE 3, magnified 4 times, was made byneedling, in a Hunter loom, a layer of rayon fibers superimposed upon alayer of polyethylene film 0.001 inch thick, .both superimposed on alayer of 32 X 28 cotton gauze. The assembly was passed through the loomtwice, at a rate of about 160 strokes per square inch per passage,making a total of somewhat over 300 penetrations per square inch offilm. Both the rayon fibers and the cotton gauze were dissolved away bysolvent and swelling techniques not affecting the film, to leave thebase film 12 of FIGURE 3 perforated with minute apertures 1 6. In thiscondition, the base film is still essentially non-porous, being or morecontinuous film with the apertured area constituting 25% or less oftotal film.

If the fiber-free apertured film of FIGURE 3 is now heated to itssoftening point while free from restraint, the film area .as a wholewill undergo some shrinkage and the holes will be substantially closed,In combination with needled fibrous bundles thrust through the film,however, the film is not free to shrink in area, but is restrained bythe presence of the bundles. Heating of the film to its softening pointcauses the film to draw together around the fibrous bundles,particularly if pressure is employed. By this process, the fibrousbundles are more firmly bound to the film, but the film remainscontinuous and unbroken between the punched fibers, forming a moisturebarrier.

I have found that quite different and unexpected results are obtained ifthe assembly of film and fibers, plus substrates if used, is heated notjust up to the softening point but ,actually into or beyond that pointbut below the point at which the film becomes completely fluid. FIG- URE4 represents the fiber-film fabric assembly from which the film ofFIGURE 3 was produced, after heating to C., a figure above the softeningpoint of polyethylene, and after removal of fiber and fabric as before.In FIGURE 4, the film substance 12 is no longer inv the form ofa-continuous film, but has retracted into an open, porousreticulatenetwork marked by large and irregular holes 22. The film has beenconverted from 75 or more closed area to 75% or more open area. Thenumber of openings in the film has decreased by over 50%, and theiraverage size has greatly increased. At the same time, the thickness ofthe network of FIGURE 4 is about 0.012 inch, measured by a Starrettgauge No. 170, as compared with a thickness of 0.001 inch for the filmof FIGURE 3. In this softening and retracting process, there is-apronounced bonding of the fibers, reinforcing the integrity of thefabric, and a greatly increased resistance to delamination or fibershedding without any sacrifice in the desirable loft, softness andporosity of the material. In general, it is preferred that the film beat least 50% open area.

The invention will be illustrated examples:

by the following Example 1 A fibrous web of 1.5 denier viscose rayonfibers, weighing 168 grams per square yard, was needled through apolyethylene film 1 mil thick by passing twice through a Hunter needleloom at a total needle penetration rate of about 300 per square inch.The product was then heated to 320 F. for one minute in an oven.

Before heat treatment. the fibers could readily be separated from thefilm by pulling, and the tensile strength was 6.3 pounds per inch widestrip. The air porosity was low, after heating, the fibers resistedremoval from the film by pulling, the tensile strength was 23.5 poundsper inch wide strip, and the porosity was substantially equal to theporosity of a similar needled sample containing no film.

An additional advantage derived from the process of this invention liesin the fact that products made with no secondary substrate, as inExample 1, are heat scalable. When the product of Example 1 wasfoldedupon itself with the faces bearing the polyethylene network facingeach other and the two layers were pressed with a hot sealing iron, avery strong bond was formed, and the two layers could not be separatedwithout total destruction of the fabric. After removal of the rayonfibers with sulfuric acid, there was left two layers of polyethylenefilm, strongly sealed together, each resembling the reticulated plasticnetwork of FIGURE 4. Since both networks are very porous, a heat-sealedbond of this type is also very porous, transmitting air and moisturevapor very readily.

The process of this invention, therefore, is advantageous when it isdesired not just to increase the tensile strength of a needled nonwovenproduct, but to render the product capable of heat-sealing to itself orto other materials with the formation of a bond that is tenacious andair permeable. The air-permeable heat-sealed bond appears to be due tothe fact that once the punctured film has been transformed into areticulated network, the properties of which are described more fullybelow, so much film substance has been retracted into the peripheries 12of the large and irregular openings 22 (FIGURE 4) that there is littleor no tendency for the openings to become closed over under theinfluence of heat and normal heat-sealing pressures. L1 the field ofneedle-punched nonwoven blankets, for example, this allows theheat-sealed application of inexpensive selvages, or of decorativepatterns of other materials to the blanket surface, or of the anchoringof heating filaments between layers of the product of Example 1 toproduce an inexpensive electric blanket.

Example 2 This was similar in all respects to Example 1 except that thefibrous fleece was 156 grams per square yard of 3 denier acrylic fibers.The unheated sample had a tensile strength of 5.7 pounds per inch Widestrip. The heated sample was much more resistant to fiber shedding andhad a tensile strength of 12.8 pounds per inch wide strip.

Example 3 A fibrous web of 5.5 denier rayon fibers, weighing 165 gramsper square yard, was needled through a layer of 1.5 mil polyethylenefilm and through a layer of 32 x 28 cotton gauze which underlaid thefilm. The needling operation was conducted as in Examples 1 and 2.

When the fibrous layer and the gauze-film layer were placed separatelyin the jaws of an Instron machine, the needled assembly showed adelarnination strength of 1.8 pounds per inch Wide strip. After heatingthe product as 6 in Example 1, the delamination strength was 5.0 poundsper inch wide strip.

Before heating, the product had a porosity of only 42 cubic feet of airper square foot per minute at one-half inch pressure dro most of thetransmission being through the needled fibrous bundles disposed in theirindividual apertures. After heating the product to above the meltingpoint of the film, the air porosity increased almost tenfold, to 398cubic feet of air per minute.

All three of the above products were soft, strong, ous, and conformable,with a textile drape and hand.

Example 4 A fibrous web of 3 denier polyethylene terephthalate fibersweighing 76 grams per square yard was needled through a layer of 1 milpolyethylene film and through a layer of nylon mesh screeningunderl-aying the film. The nylon screen was composed of woven nylonmonofilaments, in a 24 x 20 count, and weighed 200 grams per squareyard. Needling was as in Example 1.

In the material as prepared, the fibrous layer could be more or lessreadily pulled away from the fihn-nylon mesh substrates. After heatingas in Example 1, it was impossible to separate the fibrous layer fromthe substrates without breaking a substantial percentage of the fibers.The air porosity was 335 cubic feet of air per minute.

In each of the above examples, dissolving out all ingredients except thepolyethylene left a porous, open-meshed network of polymericthermoplastic filaments, irregular in contour and interconnected todefine irregularly shaped apertures. The filaments of the network (12 inFIGURE 4) were from five to ten or more times as thick as the thicknessof the film from which they had been derived, but the network was soopen and porous that it was quite flexible, and did not detract from thesoftness and the drape of the reinforced needled nonwoven fabrics andlaminates. The needled fibrous bundles extending downwardly through thefibrous fleece and through the film, and through the substrate ifpresent, are not individually disposed each through a separate anddiscrete aperture with unbroken film extending between apertures, as isthe case before treatment, but are anchored firmly to the edges of thepolymeric filaments which compose the irregular network. In the case ofExamples 3 and 4, where a fabric substrate was used, the polymericnetwork was in turn firmly bonded to the fabric substrate, and could notbe mechanically removed therefrom without destroying the network or thefabric. If the fabric substrate is removed by solvent or swellingaction, the pattern of the fabric is found to be engraved in intaglio onthe underside of the porous polymeric network derived from the film, thepattern being actually undercut in places attesting to the flow of filmsubstance around the yarns of the fabric substrate.

Apart from its utility in strengthening needled nonwoven fabrics andrendering them heat-scalable, as set forth above, a reticulated plasticnetwork as illustrated in FIGURE 4 has independent utility in its ownright as for example a replacement for film which has been locally slitand then expanded, or pressure-embossed and then stretched, to form anaperture-d plastic film used for packaging or decorative purposes. Suchproducts are Well known in the packaging art, and are made bymechanically stretching a suitable plastic film into which a patternedset of discontinuities has been introduced into the film substance. Theprocess of this invention provides a reticulate plastic network in arelatively simple manner and without the need for expanding tenters orother stretching devices, as illustrated by the following example.

por-

Example 5 A sheet of 1 mil polyethylene film Was run through a needleloom and punctured at a rate of approximately 300 penetrations persquare inch. If such a film is heated while free to move, it willshrivel and shrink in overall 7 area, and the majority of theperforations will tend to become smaller.

If, however, the film is restrained from exerting any substantialoverall area shrinkage during the heating process, as by confining itbetween two Wire metal screens of 14 x 14 mesh, with a highly crimpedweave, while heating to 320 F. for three minutes, the reticulatestructure of FIGURE 4 is obtained. In said structure, the minutepunctures of FIGURE 3 have been replaced by a pleasingly irregularpattern of larger openings, fewer in number, and rimmed at theirperipheries by interconnected plastic filaments of substantial strengthand thickness compared to the original film.

It is desirable in this process that the restraint against shrinkage beapplied locally over the face of the punctured film, so that it isexerted at a multiplicity of points within the area of the film. The useof peripheral restraint alone is liable to lead to the formation of avery few large openings and a product of decreased utility. The use oflayers of Wire screen, or similar rough surfaces, seems to afford amultiplicity of discrete points across the face of the film, at whichpoints the shrinkage tendency is locally impeded, so that the puncturesin the film do not seal up while the film is passing through theretraction-temperature zone, but instead the film regions around thepunctures are locally tensioned, this tension plus the surface tensionof the softened film drawing the polymer into the desired configurationshown in FIGURE 4.

Although the above examples illustrate a needling operation conducted inone direction, it will be apparent to those skilled in the 'art thatneedling through both the upper and lower surfaces of a laminate mayoften be desirable. This is especially true when it is desired to attacha fibrous web or fleece to both faces of a film, as in the formation ofa blanket material such as is illustrated in the following example:

Example 6 Two fibrous webs of 3 denier randomly-arrayed viscous fibersweighing 120 grams per Square yard were needled, one web on each face,into a polyvinylidene film one mil thick by two passes through theHunter loom as in previous examples, needling first from one face of theassembly and then from the reverse face. The laminate thus formed had atensile strength of 5.7 pounds per inch-wide strip, and was difiicult tobreathe through. After heating to 375 F. for one minute, the materialhad a tensile strength of 13.7 pounds per inch-wide strip, and wassubstantially as easy to breathe through as a pair of needled webscontaining no film.

Such a characteristic degree of attachment of needled fibrous webs to asubstrate is exceptional, especially when combined with a high airporosity, making such products eminently suited for use as garmentlinings, porous supportive elements for the foundation garment andbrassiere trades, blankets, and the like.

Having thus described my invention, I claim:

1. A porous and delamination-resistant needled nonwoven composite fabriccomprising at least one layer of textile-length unspun and unwovenfibers with at least some of said fibers aggregated into fibrous bundlesdisposed in a direction generally normal to the plane of said fabric andat least one layer of a heat retractable polymeric, thermoplastic filmmaterial in the form of a unified, porous, reticulate network consistingsolely of interconnected irregular filaments composed solely of thesubstance of said film,

said film material having a lower melting point than said fibers,

at least some of said fibrous bundles extending through said filmmaterial network and being bonded thereto by the substance of said film.

2. A fabric as claimed in claim 1 wherein said film network provides atleast 50 percent open area.

3. A heat-sealed laminate comprising at least one layer of a productaccording toclaim 1,

said layer being bonded by means of said network of thermoplasticpolymeric material to a second layer of material by means of heat andpressure.

4. A porous and delamination-resistant needled textilelaminatecomprising at least one layer of textile-length unspun and unwovenfibers and at least one secondary substrate layer some at least of saidfibers being aggregated into fibrous bundles disposed in a directionnormal to the plane of said fabric and extending downwardly through saidlayer of fibers and through said substrate layer,

at least one layer of a heat retractable polymeric, thermoplastic filmmaterial in the form of a unified, porous, reticulate network consistingsolely of interconnected irregular filaments composed solely of thesubstance of said film interposed between said layer of textile fibersand said substrate layer at least some of said fibrous bundles extendingthrough said film material network with said textile fibers and saidsubstrate layer being bonded thereto by the substance of said film, saidfilm material having a lower melting point than said fibers.

5. The product according to claim 4 in which the secondary substrate isa fabric.

6. The product according to claim 4 in which the secondary substrate isa layer of foamed elastomeric polymer.

7. A method for producing a porous and delaminationresistant needledtextile nonwoven fabric which comprises assembling a fleece of unspunand unwoven textilelength fibers, said fibers being predominantlyarrayed in a plane, disposing said fleece on a continuous layer ofcontinuous film of thermoplastic polymeric material heatretractablerelatively to said'fleece, said thermoplastic polymeric material havinga melting point than said fibers, needling at least some of the fibersof said fleece through said continuous film,

lower thereby producing a multiplicity of'openings through said film andgrouping some of said fibers into the form of a multiplicity of fibrousbundles directed through said fleece and through said film openings in adirection generally normal to the main plane of the film,

and heating the assembly above the softening point of v saidthermoplastic heat-retractable film but below the point at which thefilm becomes completely fluid for a period of time sufficient to retractsaid film relatively to said fleece while restraining it by said multiplicity of fibrous bundles directed through said film to convert saidfilm into a unified, porous reticulate network consisting solely ofinterconnected irregular filaments composed solely of the substance ofsaid film, at least some of said fibrous bundles extending through saidfilm material network and being bonded thereto by the substance of saidfilm. 8. A method as claimed in claimed 7 wherein the open area of saidnetwork is at least 50 percent thereof and the thickness of saidfilaments is at least 5 times that of the original film.

9. The process of producing a heat-sealed which comprises producing anonwoven fabric according to claim 7, and sealing said fabric to asecond layer of material by means of heat and pressure. 10. The processaccording to claim 9 in which said second layer of material is anotherlayer of nonwoven fabric. 11. A method for producing a porous anddelaminalaminate tion-resistant needled textile nonwoven fabric whichcomprises assembling a fleece of unspun and unwoven textilelengthfibers, said fibers being predominantly arrayed in a plane, 5 disposingsaid fleece on a continuous layer of continuous film of thermoplasticpolymeric material heatretractable relatively to said fleece, saidthermoplastic polymeric material having a lower melting point than saidfibers, disposing the fleece and film on a substrate layer, needling atleast some of the fibers of said fleece through said continuous film andsaid substrate layer,

at least some of said fibrous bundles extending through said filmmaterial network with said textile fibers and said substrate layer beingbonded thereto by the substance of said film.

12. The process according to claim 11 in which the substrate is afabric.

13. The process according to claim 11 in which the secondary substrateis a layer of foamed elastomeric polythereby producing a multiplicity ofopenings through mer.

said film and grouping some of said fibers into the 15 References Citedform of a multiplicity of fibrous bundles directed UNITED STATES PATENTSthrough said fleece and through said film openings in a direction normalto the main plane of the film into 3,241,214 3/1966 Smlfl} et a1 161 80X the substrate, 3,245,854 4/1966 Etchrson et al. 161-65 X and heatingthe assembly above the softening point of 20 3,307,990 3/1967 Homler et161-81 X said thermoplastic heat-retractable film but below the point atwhich the film becomes completely fluid for a period of time suflicientto retract said film relatively to said fleece and substrate layer whilere- ROBERT F. BURNETT, Primary Examiner. R. H. CRISS, AssistantExaminer.

